The present invention relates to improvements in sport shoes and more particularly in ski boots, of which the present modern design causes the upper, surrounding the bottom of the leg, to play an important role in the technique and practice of skiing, where the forward and/or rearward supports for the leg are constantly subjected to stress.
Ski boots provided with devices enabling the supports for supporting the skier's legs in the upper of the boot to be adjusted are already known.
In particular, two-parts ski boots exist, of which the upper pivoted on the bottom part of the shell is provided with devices for adjusting the angle of inclination of this upper with respect to the plane of the sole. These devices comprise generally complex mechanisms of which not only the cost price is high, but which also increase the weight of the boot and its outer dimensions, this brings about certain drawbacks when practising skiing and more particularly for high level skiing. Moreover, these different mechanisms are difficult to integrate in the aesthetics of the boot, as they generally project from the outer periphery thereof. Ski boots are also known which are put on from the rear, and which consequently comprise a particular arrangement of the upper pivoted on the bottom part of the shell. In the case of this boot design, U.S. Pat. No. 4,104,811 filed by applicant on Mar. 28, 1977, also discloses a device for adjusting the point of fastening of a strap surrounding the upper of the boot. This strap for adjusting the stiffness and the inclination of the upper with respect to the bottom part of the shell has the drawback, despite the progress which it brings, of not being sufficiently progressive in its deformations when it is subjected to the stresses of the leg during skiing.
Ski boots are also known which comprise elastic bands arranged on the upper of the boot, the function of which is to ensure the tight enveloping of the leg by said upper, in the case of a boot design not having an articulation between the upper and the bottom part of the shell. The role of the elastic band is then limited to ensuring the closure of the boot around the foot, which, without this, would risk not remaining tight for all the positions taken by the leg when practising skiing.